Afterward he attended Ripon College where he appeared in a leading role in a play entitled The Truth, and decided on acting as a career. Tracy received an honorary degree from Ripon College in 1940. While touring the Northeast with the Ripon debate team, he auditioned for and was accepted to the American Academy of Dramatic Arts in New York. His first Broadway role was as a robot in Karel Čapek's R.U.R. (1922), followed by five other Broadway plays in the 1920s. In 1923 he married actress Louise Treadwell. They had two children, John and Louise (Susie).

For several years he performed in stock in Michigan, Canada, and Ohio. Finally in 1930 he appeared in a hit play on Broadway, The Last Mile. Director John Ford saw Tracy in The Last Mile and signed him to do Up the River (1930) with Humphrey Bogart for Fox Film Corporation. Shortly after that he and his family moved to Hollywood, where he made over 25 films in five years.

Tracy and Hepburn

In 1941, during the filming of Woman of the Year, Tracy began a relationship with Katharine Hepburn, who had just ended a five-year affair with producer Howard Hughes. Their relationship, which neither would discuss publicly, lasted until Tracy's death in 1967. Their relationship was complex and there were often periods where they were estranged. During one Tracy had a brief romance with Gene Tierney while filming the Plymouth Adventure.

Academy Awards

All of Spencer Tracy's Oscar nominations came in the Best Actor category.

Death and legacy

During his later years, Tracy's health worsened after he was diagnosed with diabetes, exacerbated by his alcoholism. Seventeen days after filming had completed on his last film, Guess Who's Coming to Dinner, with Hepburn, he died from a heart attack at the age of 67. The film was released in December, six months after his death.

Forty years after his death, Tracy is still widely considered one of the most skillful actors of his time. Fellow actor Van Johnson referred to Tracy as "my mentor".

Tracy was one of Hollywood's earliest "realistic" actors. Actors have noted that Tracy's work in 1930s films sometimes looks like that of a modern actor interacting with the more stylized and dated performances of everyone around him.